1. Field of the Invention
The present invention relates generally to a motor, and more particularly to a brush DC motor with reduction mechanism.
2. Description of the Related Art
A conventional motor serves to convert electrical energy into mechanical energy. The motor can drive a load in a direct drive manner. Alternatively, in general, an independent transmission mechanism must be additionally arranged between the motor output shaft and the load. The torque output by the output shaft of the motor is adjusted and changed by the transmission mechanism and then transmitted to the load.
Conventionally, a shaft coupler or other transmission components are needed to transmit the power of the output shaft to the transmission mechanism in a relatively complicated manner. Accordingly, the power is transmitted via numerous transmission components, which abrade each other to cause a loss of part of energy. Moreover, the numerous transmission components prolong the transmission path of the power and thus lower the transmission efficiency.
In addition, the transmission mechanism is coupled with the output shaft of the motor to transmit the power thereof. However, the transmission mechanism and the motor are independent units and some components are obviously omissible for the purpose of transmission. These omissible components lead to high manufacturing and maintenance cost and will working precision. Moreover, these omissible components make it harder to fully utilize the space for the deployment.
The inventors' U.S. Pat. No. 7,211,016 discloses a brushless DC motor integrated with a reduction mechanism of planetary gear train to overcome the shortcomings existing in the prior art. It is tried by the applicant to apply the technique of the above patent to a brush DC motor as disclosed hereinafter.